SCI和EI收录∣中国化工学会会刊

›› 2015, Vol. 23 ›› Issue (3): 552-558.DOI: 10.1016/j.cjche.2014.04.001

• 化工热力学 • 上一篇    下一篇

Thermodynamic behaviors of SiCl2 in silicon deposition by gas phase zinc reduction of silicon tetrachloride

Yanqing Hou1, Zhifeng Nie2, Gang Xie2,3, Rongxing Li2, Xiaohua Yu2, Plant A. Ramachandran4   

  1. 1 State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China;
    2 Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China;
    3 Kunming Metallurgical Research Institute, Kunming 650031, China;
    4 Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
  • 收稿日期:2013-12-19 修回日期:2014-04-04 出版日期:2015-03-28 发布日期:2015-04-03
  • 通讯作者: Yanqing Hou
  • 基金资助:
    Supported by the Provincial personnel training funds (kksy201352109) and the National Natural Science Foundation of China (51374118).

Thermodynamic behaviors of SiCl2 in silicon deposition by gas phase zinc reduction of silicon tetrachloride

Yanqing Hou1, Zhifeng Nie2, Gang Xie2,3, Rongxing Li2, Xiaohua Yu2, Plant A. Ramachandran4   

  1. 1 State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China;
    2 Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China;
    3 Kunming Metallurgical Research Institute, Kunming 650031, China;
    4 Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
  • Received:2013-12-19 Revised:2014-04-04 Online:2015-03-28 Published:2015-04-03
  • Supported by:
    Supported by the Provincial personnel training funds (kksy201352109) and the National Natural Science Foundation of China (51374118).

摘要: The modified Siemens process, which is the major process of producing polycrystalline silicon through current technologies, is a high temperature, slow, semi-batch process and the product is expensive primarily due to the large energy consumption. Therefore, the zinc reduction process, which can produce solar-grade silicon in a cost effective manner, should be redeveloped for these conditions. The SiCl2 generation ratio, which stands for the degree of the side reactions, can be decomposed to SiCl4 and ZnCl2 in gas phase zinc atmosphere in the exit where the temperature is very low. Therefore, the lower SiCl2 generation ratio is profitable with lower power consumption. Based on the thermodynamic data for the related pure substances, the relations of the SiCl2 generation ratio and pressure, temperature and the feed molar ratio (nZn=nSiCl4) are investigated and the graphs thereof are plotted. And the diagrams of KpΘ-T at standard atmosphere pressure have been plotted to account for the influence of temperature on the SiCl2 generation ratio. Furthermore, the diagram of KpΘ-T at different pressures have also been plotted to give an interpretation of the influence of pressure on the SiCl2 generation ratio. The results show that SiCl2 generation ratio increases with increasing temperature, and the higher pressure and excess gas phase zinc can restrict SiCl2 generation ratio. Finally, suitable operational conditions in the practical process of polycrystalline silicon manufacture by gas phase zinc reduction of SiCl4 have been establishedwith 1200 K, 0.2MPa and the feedmolar ratio (nZn=nSiCl4) of 4 at the entrance.Under these conditions, SiCl2 generation ratio is very low, which indicates that the side reactions can be restricted and the energy consumption is reasonable.

关键词: Polycrystalline silicon, Thermodynamics, Gas phase zinc reduction process, SiCl2 generation ratio

Abstract: The modified Siemens process, which is the major process of producing polycrystalline silicon through current technologies, is a high temperature, slow, semi-batch process and the product is expensive primarily due to the large energy consumption. Therefore, the zinc reduction process, which can produce solar-grade silicon in a cost effective manner, should be redeveloped for these conditions. The SiCl2 generation ratio, which stands for the degree of the side reactions, can be decomposed to SiCl4 and ZnCl2 in gas phase zinc atmosphere in the exit where the temperature is very low. Therefore, the lower SiCl2 generation ratio is profitable with lower power consumption. Based on the thermodynamic data for the related pure substances, the relations of the SiCl2 generation ratio and pressure, temperature and the feed molar ratio (nZn=nSiCl4) are investigated and the graphs thereof are plotted. And the diagrams of KpΘ-T at standard atmosphere pressure have been plotted to account for the influence of temperature on the SiCl2 generation ratio. Furthermore, the diagram of KpΘ-T at different pressures have also been plotted to give an interpretation of the influence of pressure on the SiCl2 generation ratio. The results show that SiCl2 generation ratio increases with increasing temperature, and the higher pressure and excess gas phase zinc can restrict SiCl2 generation ratio. Finally, suitable operational conditions in the practical process of polycrystalline silicon manufacture by gas phase zinc reduction of SiCl4 have been establishedwith 1200 K, 0.2MPa and the feedmolar ratio (nZn=nSiCl4) of 4 at the entrance.Under these conditions, SiCl2 generation ratio is very low, which indicates that the side reactions can be restricted and the energy consumption is reasonable.

Key words: Polycrystalline silicon, Thermodynamics, Gas phase zinc reduction process, SiCl2 generation ratio